Chapter 5.3

Circle illustration showing a radius, a diameter, the center and the circumference.

Circle: The set of points in a plane that are equidistant from a given point known as the center of the circle.

Radius of a Circle: A segment that connects the center of a circle with a point on the circle;one-half diameter of a circle.

Diameter of a Circle: A chord that passes through the center of a circle; twice the length of the radius of the circle.

Circumference of a circle: C=3.14(d) or C=2(3.14)(r
The distance around the circle.
area if a circle: A=3.14(r)2

The circumference, C, of a circle with diameter d and radius r is given by: C=pie d or C= 2 pie r